Steam-turbine.



K. BAUMANN.

STEAM TURBINE. APPLICATION FILED JUNE 23. 19x5.

Patented Apr. 29, 1919.

1 SHEETS--SHEET"I.

INVENTGR- MGM BY v

HIS ATTORNEY IN'FACT K. BAUMANN. STE AM .TUHBINE.

APPLICATION FILED JUNE 23, 1916- I 1,302,282. v I Patented Apr. 29, 1919.

7 SHEETS-SHEET 2- INVENTOR.

HIS KTTORNEY IN FACT;

K. BAUMANN.

STEAM TURBINE.

7 SHEETSSHEET 3 INVENTCR.

- HISfI'TORNEY IN FACT BY A l I,

K. BAUMANN. STEAM TURBINE. APPLICATION FILED JUNE 23. 1916- Patented Apr. 29, 1919 INVENTOR.

HIS ATTORNEY IN FACT,

K, BAUMANN.

STEAM TURBINE. APPLICATION FILE'D Juana, 1'9l6. Patented Apr. 29, 1919 1 SHEETS-SHEET 5.

HIS ATTQRNEY IN FACT.

K.'BAUMANN.

STEAM TURBINE.

APPUCATION mm :uuzzs. was.

" Patentd Apr. 29,1919.

7 SHEETS-SHEET 6.

E I I J HIS ATTORNEY IN FACT K. BAUMANN.

STEAM TURBINE.

APPLICATION FILED JUNE 23, 19196.

Patentd Apr. 29,1919.

1 SHEETS-SHEET 1.

\ I III- III/II IIIIIIII/IIIIIII TED STATES PATENT OFFICE.

'mL BAUMANN, or ms'ron, ENoLAnn, ABSIGNOR 1:0 mm mu'rrsn WESTINGHOUSE.

ELECTRIC & UFACTURING COMPANY LIMITED, A COMPANY ORGANIZED UNDER THE LAWS OF GREAT BRITAIN.

STEAM-TURBINE.

To all whom it may concern Be it known that I, KARL BAUMANN, a citizen of the Confederation of Switzerland, and a resident of Urmston, in the county of Lancaster, England, have invented a new and useful Improvement in Steam-Turbines, of which the following is a specification.

' This invention relates t axial flow steam turbines of either the impulse or reaction type, or a combination of these types, and particularly to turbines adapted to work under a high vacuum.

The invention has for its object to provide an improved turbine of this kind in which certain constructional difiiculties inherent in a turbine of this type are overcome in a novel and practical manner, and the output for a turbine of a given speed and efficiency is considerably increased.

As iswell known, the maximum output which can be obtained in any given turbine is determined by the blade area through which the steam leaves the turbine proper. This blade area is limited by the practical difiiculties which are encountered when blades above a certain length are used.

In some cases the outlet angle of the blades has been increased in order to obtain the necessary area-for the steam to flow through.- This arrangement, however, impairs the eiiiciency of the turbine;

The last stage or stages-of the turbine. have also been constructed as a double stage or sta es, one-half only of the steam actin in eac half of the double stage. In this arrangement the steamuin the last stage or stagesflows in opposite directions necessitating large and complicated passages for guiding one-half of the steam from the preceding stage to one-half of the divided last stage or stages, and for leading the exhaust steam to the condenser. With this con struction the cost of the turbine is considerably increased and losses are caused by the formation of eddies in the steam during its flow through the gpiding passages.

According to t e present invention the turbine is so constructed that the steam flowing in "substantially thesame direction throughout a, low pressure part passes from a lurality of rows of moving'blades to the ex aust, i

Specification of Letters Patent.

Patented Apr. 29,1219.

Application filed June 23, 1916. Serial No. 105,409.

In carrying out the invention into practical eflect one or more of the rows of both stationary and moving blades or of a row of moving blades in a low pressure stageor stages of the turbine, for example, the penultimate and ante-penultimate stages, is or are constructed in multiple tiers or rings, the individual tiers in a row of blades being separatedfrom each other by circumferential dividing walls, So that the steam flowing through such row or rows of blades segregated into two or more annular portions or belts, the steam flowing through the blades in an outer tier or tiers being ex panded at a greater rate at each stage (comprising a row of guide blades or nozzles and its cooperating row of moving blades) than blades will in some cases have been fully expanded and passes either direct to the ex austor through one or more further rows of moving blades in which its remaining velocity energy is abstracted. The steam leaving the adjacent inner portion of the same row of blades will nothave been fully expanded and may either be further expanded in a final row or rows of undivided. or divided stationary and moving blades from the latter of which it. flows to the exhaust, or may be further segregated into one or more portions in one or more succeeding rows of blading some only or all of which are provided with dividing walls, .the

outer portion orbelt of steam leaving the moving bladesof some or all of such sucs ceeding row or rows passlng direct to the exhaust, the inner portion of steamirom' the last divided row of blading passin to a final row or rows of blading in whic it isfully expanded and thence to the exhaust.

Itwill thus be seen that the steam; in an outer tier or tiers is expanded at a greater rate than the steam passing through an inner tier or tiers of the same-row or rows of blades.

The arrangement above described in whi h the rows of blading are provided with circulnferential dividing walls so as to form multiple tiers, enables the blading in each of the individual tiers ofv a row to be so designed as to obtain the best. efliciency for the varying peripheral velocities obtaining in each tier. It is, in some cases, however,

. desirable todesign the blading of an inner tierv not with. the object of attaining the maximum efliciency in that tier but with the object of securing the flow of a large amount of steam through such inner tier, at the same time maintaining the mechanical strength necessary t support the outer tier or tiers of moving blades. This can be done either b not expanding the steam far enough to ohtai'n the best efliciency or by increasing the outlet angle of the blading or in bot of these ways.

I have found that a very satisfactory way of accomplishing the above objects is to employ blading of the reaction type in one or more of the tiers and of the impulse type for the other tier or tiers of the same row or rows of blading. For example, for the intermediate rows f blading where considerable differences in the rate of expansion of the steam in the various tiers take place, I prefer to use blading of the reaction type forthe inner tier or tiers and blading of the impulse type for the outer tiers.

or rows 0 bladingwhere thepressure at which the steam .leavin" the blades is substantially uniform over" the whole of the blade area in such final row or rows.

In some cases itmay be desirable to design the blading in the inner tier or tiers of the intermediate rows to 'form guide passages onlyfor the steam, the pressure and velocity, of the steam being substantially the same at the entry and exit ends of a stage. In other cases the pressure of the steam may be reduced and its velocity correspondingly-ins creased without, however, abstracting any of .its energy while passing through the inner tier or tiers of blading. Thus themoving blades of an inner tier or tiers are sometimes So designed that the .steam passage between them narrows from both edges, especially from the outlet edges toward the center. At

. other times the blades are so designed that the passage between them is of approximately constant width.

which mag:

In other cases the blading 'is so designeg that substantially no change in the directio .of the ,flow of steam takes place during its passage through the stationary blades of the 1nner tiers, in which cases some or all of such blades may be omitted.

The invention may be carried into efli'ect in a Variety of wavs, some of which will now be described with reference to the accompanying drawings, in which Figures 1 and 2 are conventional longitudinal sections of the upper half of turbines of the im ulse type constructed in accordance with t is invention. Fig. 3 is a part of a view similar to those of Figs. 1 and2, showing the invention applied to adwell known type of reaction turbine, and also illustrating sections of parts of'the blading. Fig. 4 is a sectional view of a turbine in which the high pressure stages are of the reaction type, and in which the low pressure stages are of the well known disk construction, the blading being either of the reaction or of the impulse types. Fig.

5 1s a sectional view on. an enlarged scale of the blading on the line V-'V of Fig. 1,-

mentary reproduction of the last rows of the blading of the turbine illustratedin Fig. 2, Figs. 8," 9, 10 and 11 being sectional views respectively on the lines VIII-VIII,

Fig. ,6 is a similar view of the blading on the line VI--VI of Fig. 1. Fig. 7 is a frag- 12 is a sectional View also on an enlarged scale of an alternative form of blading be adopted in place of those shown in ig's. 9 and 10, or of the final row of stationary blades shown in Figs. 6 and 11. Figs. 13, 14 and 15 are fragmentary views showing in section alternative forms ofblading which may be used in the inner tiers of blading in the turbines shown in Figs. 1 to 4. Fig. 16 is a detail constructional view hereinafter explained. Fig. 17 is a detail view of Figs. 18 and 19 sections on the lines XVIII-XVIII, XIXXIX respectively of Fig. 17 hereinafter explained. Figs. "20,

21, 22 are enlarged detail views showing various forms of packing which may-fbe-employed between the stationary and-moving blades. Fig. 23 is a fragmentary diagrammatic illustration of another form which a turbine, to which the present invention is applied, may take. Similar parts are indicated by the same reference numerals in the various figures of the drawings.

Referring now to Fig. 1, the turbine cylinder is indicated at 1 and the exhaust casing at 2. The turbine shaft is indicated at 3 and the steam inlet at 4. The inlet nozzles "are shown at 5 and the first wheel at'6 provided with noving blades 7 as usual. Said nozzles and moving blades comprising the first stage are succeeded by further rows of stationary nozzles 8, "8 and moving blades 9,

is 9,forming subseguent stages, in the usual way. The row stationalyblades-l0 and cobperating moving blades 11 are each provided witha circumferential wall 12, 13 respectively, which dividethe blades 1Q, 11 into inner and outer portions. This divid- 'ing wall may be-formed by providing the blades with lugs or flanges at an intermediate point in their length. The outer portion of the blades 10,- 11, forming the outer tier,

, namely that tier lying farthest the turfbine axis, is designed so as to expand the. steam flowing through it at a a than that at which the steam flowing through 15 eater rate the inner tier of these blades, namely that tier lying nearer the turbine axis, is ex- 1 and then passes through. the several stages 8, r

panded. The stationary andymoving blades 10, 11 are followed by a further row of stationary blades 14 and cooperating moving blades 15, the. former being here shown as consisting of two portions, a mam "portion 22 and an outlet portion 23. As illustrated,

the stationary blades 14 are supported in.

position in a diaphragm 16 which is held in position by means'oflugs 17, 18 enga g with aweb 19 extending between the tur ine cylinder 1 and a guide wall 20 in the exhaust casing 2. y The outer ends of the stationary guide blades 14 in the diaphragm 16arepro- {rided with an inclosing wall or rim 21 which separates the steam passing through the stationary blades 14: from that leaving the outer portions of the moving blades 11.

The operationof the turbine, constructed as above described, is as follows:

The steam admitted through the inlet noz-.

zles flows through the moving blades 7 9, 8, .9 and so on in succession in the usual way until it reaches the fixed guide blades and moving blades 11 where the steamis divided into tyvo portions bythe circumferential walls 12, 13, the outer portion of steam, namely that flowing through the portions of these blades lying farthest from the turbine axis, being expanded to the pressure in the exhaust of the turbine, and passing from the outer portion of the moving blades 11 direct-into the" exhaust casing 2. The

inner portion ofsteam, that flowing through the Portions of the blades 10, 11 lying near 1 est the'turbine axis, is only partially expanded and after leaving the inner portions of the moving blades 11 passes through the station'ary guide blades 14 and. moving blades in which the steam is fully expanded, and

after leaving the moving 1 blades 15 also passesdirect into the exhaust casing 2 of the turbine. f

Thesteam leaving the inner portions of the stationary and moving blades 10 and 1=1.is' thus at a higher pressure than the steam leaving the outer portions "of said blades and it is-necessary therefore that the clearance space be.-

tween the circumferential guide walls 12 anfd .13 and between the circumferential guide wall 13 and the outer rim 210i the diaphragm 16," should be as small as possible. This is, best efi'ected by; meansof a thrust block located as near as possible to the low pressure stages and by providing the edges of the circumferential wall 12 and of the rim 21 with glandstrips,several forms of which are hereinafter described and shown in Figs. 20, 21 and 22of the drawings.

It will be seen that with a turbine constructed and operating as above described,

constitutingwhat may be'tel'med-a multiple exhaustY-turbine; the total area of the moving blades t through which the steam leaves the turbine proper is that of the final row of moving blades 15 plusthe area of the outer portion of the moving blades 11., In this way the desired increased leaving blade area. necessary in order to secure an increased output is obtained without necessitating the employment of a final row of moving blades of 1nordinately great length orof a divided stage or stages through the blading of which the steam flows in opposite directions.

Alternatively, for the same. output a smaller blade angle can be utilized for they I leaving stages than with a turbine asheretofore constructed having but a singlefinal row of blades of the same blade height, and thus a better efficiency for the leaving stages,

and consequently for the whole turbine, can v be obtained.

The energy extracted per unit weight of steam in the outer tiers of stationary blades 10 and moving blades 11 will be approximately equal to the energy extracted per unit weight of steampassing throughthe inner tiers of stationary blades 10 and moving. blades 11 and the succeeding final row of stationary, blades 14" and moving blades 15. In the construction illustrated, the steam fiowin through the inner tiers of stationary bla es 10and moving blades. 11 is expanded at a lower rate than the'steam flowing through 'the outer tiers of; stationary blades 10 and moving blades 11, the remaining expansion of the steam flowing through the inner tiers of saidblades taking place in the. guide blades 14 and moving blades 15. The mean peripheral speed of the outer tierof moving blades 11 isconsiderably greater than the mean peripheral speed of themoving blades 15, consequently a greater amount of expansion canefiiciently be utihzed 1n said outertier; infect the expansioncan be distributed in'such a manner that the efiiciency of said outer tier may be higher than that of the final stage 14, 15.

Figs. 5 and 6. are sections drawn to en- 1 s., larged scale showing one arrangement of blading which may be used in theifinal stages of the turbine illustrated in Fig. 1,

type. In Fig. 6 the stationary blades 8 and moving blades 9 are, of course, the'same as the blades 8, 9 in Fig. 5, whereas the stationary blades 10 and moving blades 11 of the inner tiers-of those blades are of a type specially designed with a view to passing a large quantity of steam through the available blade area, by which-term is meant the total area of the complete ring of blades measured on a plane perpendicular to the shaft. The inner tiers of the blades 10, 11 are also designed for a relatively small expansion only of the steam flowing "through them, andalso with a view to providing the moving blades with the necessary mechanical strength. In order that a largequantity of steam may be passed through them the blade angles adopted for the blades of the inner tiers are considerably greater than the blade angles adopted for the outer tiers. The expansion in the inner tiers of this stage occurs mainly in the moving blades 11 in. which the steam velocity is increased beyond that existing in the inner tier ofthe guide blades 10, as the space between the moving blades is reduced on account of the thickness which it is desirable to give to the inner portion of said blades to afl'ord the necessary mechanical strength.

In order to obtain the maximum strength of the blades for a given steam velocity it is necessary to arrange that the expansion shall'take place chiefly at the entrance of the passages between the moving blades 11, and that the velocity shall remain practically constant while the steam is passing through the remaining portions of the pas sages between the blades, the leaving angle being arranged. as shown in Fig. 6 so that the width of the remaining portions of the passages between the blades is practically constant.

The final rows of guide blades 14 and moving-blades 15 are, as shown in Fig. 36, of the usual type as regards the blade angles em ployed. It is, however, necessary to increase the width of the guide blades 14 and consequentlv the distance between the moving blades 11- and 15, in order/to avoid the formation of eddies and obtain a satisfactory flow of the steam passing through said guide blades, as well as to provide the necessary space for the/steam leaving the outer tier of mowing blades 11.- In the construction shown in Figs. 1 and 6, the guide blades 14.

consist of two portions, namely mainportions 22- which, in the construction shown,

are castin one piece with the diaphragm 16, and outletportions 23, which are preferably formed separately and either cast or afterward inserted into a frame 39 form- 1 stant.

ing art of the diaphragm 16. The stationary 'lades 14 need not, however, necessarily be constructed in two portions, as "shown in Fig. 6, but may be formed as shown in section in Fig. 12, in one piece.

In some cases, in order to provide the necessaly strength the moving blades 11 and and 15.

Fig. 13 shows a design in which the outlet angle of the guide bladeslO is smaller than in Fig. 6 and is such that having regard to the velocity of the moving blades 11, relative to that of the guide blades 10, the steam enters said moving blades in an approximately axial direction. In this design a relabe adopted, are illustrated in Figs. 13,

tively greater part of the expansion occurs in the guide blades 10 than ip the corresponding guideblades 10 shown in Fig. 6. The inlet ortions of the moving blades 11 are reduced to an edge as shown, so as to prevent eddies where the steam meets the edges of the blades. The expansion through the moving blades 11 takes place chiefly at the inlet ortioh of the blades, as is the case with the b ades 11 shown in Fig. 6, practically no expansion taking place during the passage of the steam through the remaining portion of the moving blades 11 of Fig. 13, the leaving angle being arranged as shown so that the width (if the remainder of the passage betweenthe blades remains practically con- In the design shown in Fig. 14 no change in the direction of the steam takes place during its passage through the guide blades 10.

The blades can, as shown, be'flat and located in a plane parallel with the axis of the turbine, or they maybe inclined in either direction with respect to the. turbine axis. As no appreciable change in the direction of the steam' takes place some or all of the blades 10 may be omitted. If these blades are omitted the velocity 'of the steam may be varied as desired either by decreasing or by increasing'the radial height of the pas- If the inner tier of, guide/blades is V sage. omitted some means for directing the steam flowing from one row of moving blades to the next, to take the place'of the inner circumferential wall of the guide passages, must be provided. This may take the form v of i a cylinder extendingbetween adjacent mechanical energy being a stracted from rows of moving. blades and suitably. sup

ported in the proper position from the shaft or from the wheels.

The moving blades 11 shown in Fig. 14 are designed in such a manner that no expansion of the steam during its passage through them takes place and the direction of the steam leaving is the same as the direction of the steam enterin the blades, no

the steam during itspassage through them. and consequently no appreciable change in its pressure. occurs. ,The moving blades 11.

are of an f sha e, as shown, the central portion being straight and of uniform thickness, and thesides reduced to an edge, so

a that the steam passage between two ad acent bladesis of ractically constant width. This design enab es blades of the necessary mechanical strength to be provided which do not change the velocity of the steam to any extent during its passage between them.

1 The. guide blades shown inFig. 15 are or the same type as those shown in Fig. 14. The moving blades 11 are flat and more or less inclined relative. to the axis of. the turbine, being reduced to. a fine edge at both sides, especially at the dhtlet side, the center portion f, the blades being preferably of substantially uniform thickness. A passage is thus formed between adjacent blades in whichthe pressure of the steam is reduced turbinedisk or ShaftQtheouter tier of movat the entrance of the blades and the velocity,

increased as it flowstoward the middle portion of. thevpassage thevelocity being reconverted into ressure bythe gradually increased widt of the passage toward its outlet.

This design of moving blades lends itself articularlyto the construction in which the mner tier of blades is made solid with the ingblades being secured to the rim of the disk or shaft by rivets or in any other suitable manner.

a reference to The various designs which the blading of the inner and outer tiers of a rowand the final rowma take, described above with have been given by way of example and as ,indica'tingsome -of.,the"i nore advantageous designs'which canbe employed. The blading of the circumferentlally divided tiers may sometimes be of the same character in two or more of the "individual tiers of a row. i The expansion'however taking place at different rates in the several tle'rs of a row.

; The blades may in some cases also have the same inlet and outlet angles in the various" tiers of a row. Frequently also it will be found advisable to provide an outer tier of a rqwwith a greater numberof blades than an nner tier of the same row.

igs. 5, e, 12, 13, 14 and 15,

Fig. 16 shows a modified form which the outer inclosing wall of the stationary blades:

The outer wall or (rim 21 is here shaped so as to may, with advantage, assume.

change the direction of the steam leaving the outer tier of the moving bladesll from a substantially axial into a substantially radial direction during its passageto the e);- haust casing. In order toprevent, as far as possible,- the formation of eddies, due to the rapid change of direction of the steam, an

additional guide 24 may be provided which,

will separate the steam flowing'to the exhaust into two portions. More thanone of such additional uidesmay of coursebe used if desired, and t ey need not necessarily be supported from the inclosing rim 21, as here illustrated, but may be attached to the tur bine cylinder or exhaust casing. One or more similar guides to that shown'at'2 1 in Fig. 16 may be provided for directing the steam. leaving the last row of moving blades 15. The shape given to the inclosing rim'21 and curved guide 24 will obviously do end upon the direction in which it is desire the steam leaving the moving blades should flow toward the exhaust, as the change in the flow of the steam need not" necessarily be from an axial into a radial direction. 1

roe

are again of the impulse type and those of y the inner tiers are of the reaction type.

The blades j of the inner and outer tiers are respectively shown in section 1 in Figs. 18 and 19, these figures being taken on the llnes XVIIIXVIII, XIX-XIX of Fig. 17. This combined use of impulse and reaction blading, in one and the same row 1s, in some cases, also' adapted to obtain the best efficiency for the last. stage of the turbine, as well 1 as mechanical strength for the roots of the moving blades, bladlng of the reaction ty e being more suitable for the inner tier owing to the relatively higher steam velocities obtained in the passages between. the moving blades which enables the roots of the moving bladesto bemade stronger. In other cases the same type of blading will be used for both inner and outer'tiers but the outlet angles'of thestationary blades in the inner and outer tiers may be difl'erent; I' sometimes omit the stationary. dividing wall 25 but retain the dividing wall :26 in order to separate the steam flowin through theinner and outer portionsof t e moving blad s and prevent .type of packin eddies which may arise due to the great difference in steam velocities resulting fromthe great difference in the peripheral velocities between" the inner and the outer tier.

Fig. 20 shows on an enlarged scale the shown in Fig. 1 as being used between t e circumferential dividing walls of the stationary and movin blades 10, 11 and between the moving b ades 11 and the. inclosin blades 14. As sfiown in this figure the side of the circumferential wall 12 adjoining the circumferential wall 13 is sharpened to a knife edge so as to reduce the danger, of heating in case rubbing takes place between the walls 12 and 13. The inclosing rim 21 is shown as being provided with a gland strip 27 of 'a well known type for a similar reason. s Fig. 21 shows an alternative form of I packing strip 28 of a well known type which 3 are, however, in this case secured to the cir may be employed. The packing strips 28 cumferential walls 12 and 21 by rivets 29 thus providin a very substantial mechanical design an one in which the replacement of thestrips where necessary is much facilitated- Fig. 22 shows a further arrangement in which the circumferential wall 13 is provlded with proJections 30 which are so located with respect to the packing strips 28 asto guide any leakage steam in substantially the same direction as the working 7 steam passin through the turbine. The direction in w lch anyleakage steam will be caused to flow with the arrangement shown in thisfigure is indicated diagrammatically by the stream lines.

Referringnow to Fig.2, this shows acoustruction which may be adopted in those cases where it is necessary to pass greater volumes of steam through the low pressure stages of the turbine than in the case of the turbine described with reference to Fig. 1. In other words, for similar steam condltions and efiiciencies the output of the turbine can, with thisconstruction, be considerably increased. In the turbine shown in Fig. 2 the steam flowing through the in? 'ner. t1ers of the circumferentially divided stationary and moving blades 1O, 11 is further segregated by circumferential division walls 31, 32in the succeeding stage comprising a' row of fixed blades 33 and moving blades The steam passing through the outer t1er of the stationary and moving blades 33, 34 is expanded down to the. res- I sure .in the exhaust to which it directly ows on leaving the outer tier of moving blades 34-. The steam expandin at a low rate during its passage through 1; e inner tiers of the stationary and moving blades 33, 34 is again segregated into two portions by ci rmmfer-v wall 21 ofv the stationary,

ential dividing walls 35, 36 in a further succeeding stage comprising stationary and moving blades indicated at 37, 38, respec-. tively. The steam passing through the outer tier of the stationary and moving blades 37, 38 is expanded down to the pressure of the exhaust and on leaving the outer tier of moving blades 38 passes direct into the ex-- haust casing 2. The energy remaining in the steam after. flowing through the inner tier of the stationary and moving blades 37,

38 in which it is expanded at a low rate is utilized in a final stage comprising stationary blades 14 and moving blades 15 in a manner already described with reference to Fig. 1.

It will be seen that in a turbine constructed as shown 'in Fig. 2 the total blade area through which the steam leaves the turbine proper is approximately increased by the blade areas of the outer tiers of the moving blades 34 and 38 as compared with the construction illustrated in Fig. 1.

One arrangement of blading which may be adopted in a turbine of the kind illustrated in Fig. 2 is shown for -example in Figs. 7 to ,11, inclusive. Fig. 7 it will be seen, is a reproduction of some of the low pressure stages of Fig. 2 and Figs. 8, 9, 1O

and'll are sections of the blading in Fig. 7 taken respectively on the lines VIII-VIII, IXIX, XX and XI -XI. The manner in which the turbine described and illustrated in Figs. 2,7, 8, 9, 10 and 11 operates will be readily understood from what has been said in connection with Figs. 1, '5, 6 and'12, it being understood that in the turbine illustrated in Figs. 2, 7, 8, 9, 10 and 11 also various alternative designs and combinations of blading may be used as hereinbefore fully set forth. 7

One example of how the invention may ofthe blading is of the reaction type is illustrated in Fig. 3, the construction and operation of which, taken in conjunction with the sectional views of the blading in the low pressure stages on the lines II, IIII be applied to a turbine in which the whole and III-III and designated by these num'erals respectively, will be easily comprebended without further detailed description.

Fig. 4 illustrates still another form of turbine constructed in accordance with this invention in which the high pressure stages are of t e usual reaction type and the low pressure stages are of the well known disk construction, the blading being of either the impulse or reaction'typeor a combination of these types.

In the construction illustrated in Figs. 1 2 and 4 the movng blades ofthe low pressure stages are shown 'as being "attached to separate disks mounted on the shaft 3. In some cases it is preferable to attach some i 60 rows of moving bla or all of such moving blades directly to the. shaft itself, the shaft in such cases being increased in diameter and provided with flanges or collars to which the moving" blades are secured in any suitable way. In these figures also a single exhaust casing only is shown into which the steam leaving the several rows of'moving blades passes. It is to be understood however that the steam leaving the various rows of moving blades f'may pass to separate exhaust casings and in some cases to'iseparate condensers, if desired.

A still further constructional form which the invention may take is. shown diagramvmatically in Fig. 23. In the turbine diagrammatically indicated in this figure. it will be seen that the segregated annular portions of steam each flow through a pluw rality of rows of fixed and moving blades before reaching the pressure of the exhaust and passing to the exhaust casing "of the turbine. It will alsobe observed that in "one. row of stationary and moving blades the steam is segregated into three annular portions, the stationary and movingblades in question being constructed asatriple tier- The blading may be arranged in such a Way that the ratio of the steam velocities and.

peripheralvelocities obtaining in the varioustiers is approximately constant, thus "obtaining a uniform efliciency over the whole of the various rows of blades.

From the examples hereinalbove described and illustrated it a will be evident that the 5 J steam flowing through the working passages of a turbine constructed in accordance with this nvention is divided into separate portions forming more or less complete and par- 0ftially overlapping belts of steam, the outermost belt or belts while passing through the operative blading of the turbine being expanded at a greater rate than the winner belt. or belts lying nearer the axis of the turbine.

The steam in the outer beltor belts is led away separately to the exhaust immediately it has been expandedto the full extent," and its velocity energy abstracted therefrom. I

Stated in other words, the belts of steam flowing through the turbine while in opera- 1 tion maybe likened to a; plurality of trun cated hollow cones, the 'steamfforming the smaller end of the second and any succeeding cones being derived from the steam of. 155 the preceding cone. At the baseof each of such cones the steam will have been 'fully "expanded and is conducted away to the exhaust. Thus the steam willbe led awayto the exhaust from a lurality of independent As hereinabove set forth turbines of either the impulse or reaction type, or a combination of those types, .may e constructed in ,having difierent ratios of expansion.

that. the high piessure or other sections of 'the turbine to which the inventiouis not applledmay', if desired be of any other suitable 7 0 type. .The invention isespeciallyapplicable toexhaHst turbines or mixed pressure turbines Where the, volum'eTof steam passing into the condenser is relatively large, and.

may lso be applied to tur bines constructed as'doubleflow turbines in which portions of the steam flow in oppositedirections to the exhaust. In short, theinvention may be applied to axial flow steajm turbines of many of the various existingtypes adapted to 30 operate at a high vacuum in which, as here tofore nstructed, in order to obtain a large output, blades of inordinately great. length would have to used.

, Having" now parti ularly described and ascertained. the nature of my said invention andin what manner the samei fito'he' performed, I declare that what I claimis I 1. In an axial flow steam turbine, a stage or section, rovided with means for dividing the steam hwing therethrough into annular portions having difi'erent ratios of expert. sion. a

2. In an axial flow steam turbine, a stage or section provided with bladingqstructures so arranged as to segregate the steam into separate concentric annular portions hav. ing difieient expansion ratios." 1

3. In an axial flow steam turbine, a stage or section havingblades constructed in multiple ,tiers and arranged so thatthe steam flowing through the difierent tiers will have a different ratios of expansion.

4. In an axial flowsteain turbine,a' low pressure stagev or section provided with blading means formed so as to segregate the, steam flowing through said stageor section into separate portions havingdifieren-t expansion ratios. I

5. In an axial flow steam turbine, ahigh pressure stage or section through which the pressure stage or section through which the two or more annularbodies steam flows in 6. In an axial flow'steam turbine, a stage" or section having blades constructed in mule tiple tiers formed so that the steam flowing throughthe outer tier. has a greater ratio '01: expansion thanthe steam flowing through 130 the inner tier. 7. In an axial flow steam turbine, a stage or section provided with means for segre-. gating the steam flowing therethrough .into

separate portions having different ratiosof expansion.

,8. In an axial flow steam turbine, a a

or section having superposed concentric rings or blades so' formed that the blades farthest from the turbine axis have the greater outlet an les. 7

9. In an axial ow steam turbine, a partial peripheral admission h' h pressure stage and a full peri heral a mission 10w.pressure stafie provided wi h means for segregating t e, steam flowin therethrough into p ortions having different ratios of expan- 10 slon.

In witness whereof I have hereunto subscribed my name this second day of June,

' KARL BAUMANN. Witn: I A. E. LEIGH BEANE,

Gnome]: Soon. 

